Contactless Deep Level Transient Spectroscopy Using Microwave Reflection


Contactless deep level transient spectroscopy using microwave reflection at 35 GHz is presented and it is proved to be a powerful technique for characterizing trapping levels in semiconductors without the necessity of special sample preparation. The technique consists of measuring the transient decay in photoconductivity after a monochromatic light pulse has been applied to the semiconductor. The photoconductivity after the light pulse is caused by emission of carriers from trapping levels filled during the light pulse and by scanning the sample temperature it is possible to determine their activation energy. On Si-implanted layers on LEC grown SI-GaAs substrate we have detected three trapping levels, located at 0.15, 0.18 and 0.27 eV below the conduction band, by using a 1060 nm YAG laser, and one level, 0.13 eV below the conduction band, by using a 633 nm HeNe laser. The technique has been applied to LEC SI-GaAs and no trapping levels have been observed above the EL2 level.

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Correspondence to M. S. Wang.

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Wang, M.S., Borrego, J.M. Contactless Deep Level Transient Spectroscopy Using Microwave Reflection. MRS Online Proceedings Library 209, 523–528 (1990).

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